Today there are primarily two systems for positive pressure ventilation in use, i.e. the simple T-piece or a bag. Both use a mask as an interface to the child but can also be used via an ET-tube. The two systems are easy to handle, uncomplicated and inexpensive and have been in use for many decades.
The T-piece systems are able to provide positive pressure ventilation as well as CPAP for a breathing infant but the bag systems are unable to provide CPAP for the breathing infant.
In neonatal resuscitation there is a need for both ventilation (PPV) of the non-breathing child and support by CPAP for the spontaneously breathing child. The need for both types of support is common and changes over time during the resuscitation period.
An example of a T-piece system is disclosed in U.S. Pat. No. 4,502,481, where an inspiratory tube provides a fresh gas flow from a fresh gas source to the patient mask, and an expiratory tube outlets used gas from the patient mask via a two-way exhaust valve. In the CPAP mode the T-piece system feeds pressurised fresh gas to the patient mask and outlets used gas and excessive fresh gas through a first path of the exhaust valve which is set at a relatively low opening pressure. In the PPV mode, this path is manually intermittently occluded. When occluded the pressure at the patient mask rises and fresh gas is forced into the patient. When not occluded the patient exhales. If reaching a maximum allowed pressure before the occlusion is removed, the second path of the exhaust valve opens to avoid patient injury.
Thus, the T-piece systems can also provide both PPV and CPAP. However, these systems expose the neonate to a higher imposed work of breathing than most of the specialised CPAP systems. This may lead to extended period of PPV. This could be overcome by switching between two systems—one for PPV and a specialised system for CPAP but this is unpractical in the resuscitation period. Furthermore, specialised CPAP systems are comparatively expensive.
Therefore there is a need within the technical field of PPV/CPAP treatment for neonatal resuscitation to overcome the problems that exist today. There is a need to achieve an easy switch between PPV and CPAP for respiratory support without change of equipment and to provide a low imposed work of breathing for the breathing child treated with CPAP.